Mars Corp. earned $10,000 in January, but Mars only received $7,000 of that and the other $3,000 will be received in February. Mars only expense was $2,500 for wages. Of this amount, Mars paid $1,000 during January and will pay the remaining $1,500 on February 1st. What is Mars net income for January?
A $7,500
B $6,000
C $9,000
D $4,500